Actuator Assembly for Tubular Expansion

ABSTRACT

A hydraulically powered downhole tool includes a tool mandrel ( 20 ) having an interior bore ( 22 ), and a plurality of pistons ( 26 ) each axially movable relative to the tool mandrel and mechanically interconnected by an outer sleeve ( 24 ) exterior of the tool mandrel. A plurality of mandrel sections and a plurality of outer sleeve sections each have a lower end for interconnection with an upper end of a corresponding member. A retainer ( 28 ), ( 29 ) is provided for supporting each outer sleeve section above a respective lower sleeve section, thereby exposing mandrel sections for vertical assembly.

FIELD OF THE INVENTION

The present invention relates to an actuator assembly for positioning ina well to actuate a downhole tool. More particularly, this inventionrelates to a hydraulically powered actuator assembly for suspending inthe well from a workstring and producing high forces suitable forradially expanding a downhole tubular.

BACKGROUND OF THE INVENTION

Various types of downhole actuators are used for operating specificdownhole equipment in a well. Actuators may be hydraulically powered orelectrically powered, or may be powered from axial or rotational forcestransmitted to the actuator by a workstring. Some downhole actuators arepowered by a pyrotechnic charge.

Various types of tools have been proposed for expanding a solid tubulardownhole. Many of these tools utilize an expander which is moved axiallythrough the tubular and is powered by hydraulic pressure in the tubularbehind the expander. One of the problems with this technique is that theexpanded tubular is inherently subject to high fluid pressure as theexpander moves axially through the tubular. Leaks in the expandedtubular thus decrease the effectiveness of the technique, and thepossibility of leaks reduces the recommended fluid pressure since thereis a risk that a leak may prevent movement of the expander. If a leakprevents further movement of the expander, limited options are availableto circumvent the problem, and the well may need to be abandoned.

Some tools have used hydraulically actuated expanders with fluid powerbeing supplied to the actuator by a workstring separate from the tubularbeing expanded. As disclosed in U.S. Pat. Nos. 6,763,893, 6,814,143,7,225,880, and 7,278,492, the actuator tool may include a series ofpistons which move axially to move a tool mandrel with respect to anouter housing of the tool. The pistons are arranged hydraulically in aseries, so that a significant axial force required for tubular expansionis obtained with conventional fluid pressure within the workstring andwithin the tool. By proper sizing, an actuator from 20 to 30 feet inlength is able to generate high expansion forces over a stroke length offrom 2 to 5 feet. If an additional length of tubular is to be expanded,the tool may be recocked and restroked a second or multiple times.

The disadvantages of the prior art are overcome by the presentinvention, in an improved actuator and a method of assembling theactuator as hereinafter disclosed.

SUMMARY OF THE INVENTION

In one embodiment, a hydraulically powered downhole tool axially movesan expander in a well to radially expand a downhole tubular. A toolmandrel is axially secured to the expander, and a plurality of pistonsare movable relative to the tool mandrel and are mechanicallyinterconnected by an outer sleeve or housing of the tool radiallyexterior of the tool mandrel. One or more slips supported by the outersleeve engage the interior wall of the well to temporarily fix an axialposition of the outer sleeve in the well. Both the tool mandrel and theouter sleeve include a plurality of sections each having a lower end forinterconnection with an upper end of another section. A retainer isprovided for supporting each of the outer sleeve sections axially abovea respective lower outer sleeve section, thereby exposing mandrelsections for assembly.

According to one embodiment of a method of the invention, the tool isassembled by supporting each of the outer sleeve sections axially abovea respective lower sleeve section, thereafter assembling the exposedmandrel section, thereafter axially lowering the outer sleeve sectionover the mandrel, and thereafter assembling the outer sleeve section andrespective lower sleeve section.

These and further features and advantages of the present invention willbecome apparent from the following detailed description, whereinreference is made to the figures in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an upper portion of a hydraulicallyactuated tool being assembled at the surface of a well.

FIG. 2 is a cross-sectional view of a lower portion of the actuatortool.

FIG. 3 illustrates hydraulically actuated slips for the tool.

FIG. 4 illustrates a lower portion of the tool with an expander forradially expanding a downhole tubular.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In various applications, expanders are used to radially expand a lengthof a downhole tubular so that, for example, the tubular is expanded froma run-in internal diameter of 6⅞ inch to an expanded internal diameterof 8.4 inches. Expansion of a downhole tubular may be desirable for amono-bore well system, and may also be used to expand shorter lengths ofa tubular for a seal patch, or for a liner hanger operation. In somemono-bore applications, a relatively short length of a tubular may beexpanded by a hydraulically powered downhole tool, and thereafter asubstantially longer length of the tubular is expanded by exerting anupward pull on the drill pipe workstring.

If the tubular being expanded is deep in the well, and particularly ifthe well has deviations which cause the workstring to engage the side ofthe well during an axial pulling operation, tubular expansion by pullingon the workstring may not be feasible. In other applications, thedrilling rig or the workstring itself is not able to withstand the highpulling force that must be exerted on the expander to cause the desiredtubular expansion.

According to the present invention, an improved actuator is provided foraxially moving an expander a substantial axial distance of greater thanabout 1 meter during stroking of the hydraulic actuator. If the longerexpansion of the tubular is required, the tool may be actuated, the toolmoved and reset, and the actuator tool again stroked so that a combinedlength of expanded tubular may be more than 6 meters. Any desired longerlength of tubular may be expanded by repeated stroking operations.

Referring now to FIG. 1, an upper portion of an expander tool is shownfor suspending in a well, which typically includes an existing casing(not shown in FIG. 1). The actuator tool 10 may be suspended in the wellfrom a drill pipe or other workstring 14, which is shown threadablyconnected to top sub 16. A threaded connector 18 is shown not yetthreaded to the sub 16, and is shown connected to the tool mandrel 20,which has a central bore fluid passageway 22 therein. Sub 16 andconnector 18 are shown threadably disengaged in FIG. 1, although thefunctionally similar components 32 and 34 are shown connected in FIG. 2.The tool 10 as shown in FIG. 1 also includes an outer sleeve or housing24 which includes threads 25 as shown in FIG. 1 for threadablyconnecting to outer piston 26. Hydraulic pressure in the workstring andthus in the passageway 22 may pass through gap 30 in mandrel 20, therebyaxially moving the sub 16 and tool mandrel 20 relative to the outersleeve 24 and the outer piston 26.

An intermediate portion of the tool as shown in FIG. 2 illustrates thelower end of mandrel 20 threaded to male connector 32, which isthreadably connected to the female connector 34. The hydraulic portionof the tool 10 may have a total length of 100 meters or more. The toolmay be sequentially assembled at the well site by interconnecting alower end of an inner mandrel assembly with a partially assembled innermandrel. Threads on the inner mandrel sections may be engaged with atong or other conventional equipment, thereby making up, for example,the connection between 32 and 34. During this assembly operation, theouter sleeve section 24 may be raised above the location for the innermandrel connection, and may be retained in that upward position by asuitable clasp or latch 28, as shown in FIG. 1. With the outer sleeveraised so as not to interfere with makeup of the inner mandrelconnection, the inner mandrel may be made up, and the latch 28 thendisengaged and the outer sleeve section lowered so that threads 36 onthe lower end of the outer sleeve section as shown in FIG. 2 come intomating engagement with the threads 38 on the OD of the outer piston 26.Simultaneously with the makeup of threads at the lower end of the outersleeve section, the upper end of a sleeve section threaded at 37 mateswith threads 29 at the lower end of outer piston 26, as shown in thelower portion of FIG. 2.

In FIG. 1, the tool mandrel 20 is shown disassembled, and the associatedouter sleeve or housing is raised for assembly of the mandrel 20, whichis shown in the upper portion of FIG. 2. In FIG. 2, the lower mandrelconnection is made up, and the associated outer sleeve has been loweredover this connection and is also made up. The latch 28 is removed inFIG. 2, although a threaded lock for receiving a latch bolt is shown.The outer piston 26 is then securely engaged with the section of theouter sleeve 24 and is in sealing engagement with the inner mandrel 20due to seals 42. Similarly, the female connector 34 includes innerthreads 44 to interconnect a top section of the inner mandrel withconnector 34, which has one or more outer seals 46 for sealingengagement with the interior of the outer sleeve section 24 when it islowered in place. The female connector 34 thus effectively forms aninner piston which is secured to the tool mandrel and sealed to theouter sleeve, while the outer piston 26 inversely is connected to theouter sleeve and is sealed to the inner tool mandrel. Those skilled inthe art shall appreciate that a plurality of such pistons and pistonassemblies may be provided in various tool sections which are assembledsequentially at the well site. Threads 29 or other members may be usedinstead of latch 28 to retain the outer sleeve temporarily in a raisedposition for exposure of the components of an inner mandrel connection,so that after the inner mandrel connection is made during an assemblyoperation, the outer sleeve may be lowered and the outer sleeve sectionsthen connected.

The running tool mandrel, the outer sleeve, and the pistons thus definevariable size hydraulic cavities. A series of mandrel sections, outersleeve sections, and inner and outer pistons may be provided in thehydraulic sections of the tool, so that axial forces effective stack tocreate a desired high expansion force. It is a particular feature of theinvention that the tool as disclosed herein may generate a hydraulicallygenerated axial force in excess of 1 million pounds, and preferably inexcess of 1.5 million pounds, over a relatively long length ofapproximately 7 meters.

FIG. 3 depicts a slip portion of the tool for fixing the axial positionof the outer sleeve 24 in place during a tubular expansion operation.The outer sleeve 24 as shown in FIG. 1 is thus structurallyinterconnected, e.g., threads 51, with the slip housing 52 shown in FIG.3, which includes one or more cone sections 54 for mating with similarlytapered cone sections on slips 56 with exterior teeth 57. Axial movementof the inner mandrel 20 relative to the housing 52 interconnected withthe outer sleeve 24 thus forces the slips 56 radially outward and intobiting engagement with the liner or other tubular 12.

Slips 56 are prevented from moving downward due to engagement withsleeve 74. Collet mechanism 76 is provided between the OD of mandrel 20and the ID of sleeve 74. Sleeve 74 thus includes suitable windows eachfor receiving a respective slip. Collet mechanism 76 may include upperand lower heads, and prevents the slips and sleeve 74 from movingdownward with the outer sleeve 24 and slip housing 52 during the slipsetting operation. The collets 76 are positioned about the mandrel 20and releasably engage a groove or stop on the mandrel to hold the slips54 in an upward position, so that the slips do not move downward whilebeing set. The collets 76 may open radially outward after the slips areset, and allow the tool to be reset when the setting assembly is raised.The action of the collet mechanism is thus repeatable, thereby allowingthe tool to be repeatedly stroked, recocked, and then restroked.

Keys 53 are provided in the slip housing 52 and cooperate axiallybetween slips 56 and sleeve 74 to allow for rotation of sleeve 74relative to slip housing 52. Keys 80 are also provided at the lower endof sleeve 74, and slide within axially extending slots or grooves 72 inthe inner mandrel 20 to ensure rotation of the sleeve 74 relative to themandrel 20. Thus, rotation applied to outer sleeve 24 is transmitted tomandrel 20. The slips may be set by dropping a ball on a seat 188 toraise the internal pressure within the mandrel 20 until the increasedpressure forces the pistons axially apart, thereby generating a highaxial force to set the slips and move the expander. Once the slips areset, the mandrel 20 may be moved upward relative to the slips during thetubing expansion operation.

FIG. 4 depicts a tubular 12 which will be radially expanded by thehydraulic actuator moving the expander 48 upward, thereby radiallyexpanding the tubular 12.

A safety joint (not shown) with left-hand threads may allow for latchingof the tool with the downhole expander at the lower end of the tool.Left-hand threads allow right-hand rotation of the workstring fordrilling operations and, if necessary, left hand rotation to disengagethe tool from the downhole expander. The upper half of the safety joint173 is threaded to inner mandrel 72 and the safety joint lower halfthreaded at 172 to mandrel 170.

The lower end of tube 204, when positioned as shown in FIG. 4, isconfigured to rotate the lower end of the tool, thereby reliablyrotating the bit. During a drilling operation, the lower end of the flowtube 204 which passes through the interior of the expander 48 may besealed to the lower housing 224, thereby providing a substantiallysealed flow path to the bit.

FIG. 4 illustrates one embodiment of a lower portion of an expansiontool according to the present invention which is adapted for a liner orother tubular drilling operation. The lower portion of the tool is shownin FIG. 4 may have an upper portion which is substantially as describedabove. The tubular or liner 12 with the expander 48 supported adjacent alowermost end of the liner, the mandrel 200, and the housings 222 and224, with a bit or reamer 221 at the end thereof, may first be loweredin a well, then the remainder of the tool lowered so that keyed colletheads 194 on the lowered tool connect with the threads 198 on themandrel 200. The liner 12, once expanded, may have its upper end withina casing or other downhole tubular or uncased wellbore (not shown inFIG. 4).

Sleeve 174 threaded to mandrel 170 has lower clutch teeth 176circumferentially arranged thereon. The clutch teeth 176 mate with andthus engage clutch teeth 177 at the upper end of mandrel 200. A radiallyexternal surface of the mandrel 200 includes axially extending splines182, which mate with similar splines 180 on the modified liner section178. The splines 180 on the liner section 178 similarly extend axially,and the upper and lower ends of the splines may include conventionaltapers so that the mandrel 200 effectively slides along the splineswhile torque is transferred from the mandrel 170 to the mandrel 200, andfrom the mandrel 200 to the liner 12 to be subsequently expanded,thereby allowing the unexpanded liner and the tool to be rotatedtogether as an assembly. High torque in the drill pipe workstring 14 andthus in the mandrel 20 may be transmitted radially outward from theinner mandrel to the tubular 12. The mandrel 170 includes a central bore186, and a selectively sized seat 188 for subsequently receiving a ballor other plug member.

Mandrel 170 in turn is threaded at 192 to mandrel 190. When the tool islatched into the liner as shown in FIG. 4, the upper end of mandrel 200circumferentially surrounds and is axially slidable relative to thelower end of the mandrel 170, so that upper end of mandrel 200 ispositioned circumferentially about the lower end of mandrel 170. Colletfingers 196 with lower heads 194 are threaded at 198 to the mandrel 200when the tool is assembled downhole, as discussed above, and may slideaxially relative to mandrel 170 to allow the clutch teeth to bedisengaged when the work string 12 is subsequently picked up. Flowthrough passages 202 extend from the inside of the liner section 212 tothe exterior of mandrel 190 to allow for drainage and prevent anundesirable pressure head in the tool.

Tube 204 may thus be threaded to and sealed to mandrel 190, andaccordingly moves axially with mandrel 190. Expanding members 48 aresupported adjacent the lower end of liner section 178, and may bethreaded to the liner section as disclosed in U.S. application Ser. No.11/803,389, hereby incorporated by reference. Lower housing 222sandwiches the expander 48 between lower inwardly formed section 228 ofthe liner 212 and housing 222. For the embodiment depicted in FIG. 4,sleeve 230 may be externally threaded to internal threads on section 228of the liner. Sleeve 230 is prevented from moving upward by engagementwith shoulder 232 on mandrel 200, thereby rotating mandrel 200 with thelower housing 222. Sleeve 230 thus acts as a positive stop to preventupward movement of the expander 48 and the liner 212 prior to activationof the hydraulic power section of the tool. As shown in FIG. 4, thesection 228 of the liner is radially inwardly formed to reduce thethickness of the sleeve 230 without increasing the thickness of theliner.

Housing 222 is threaded to the lower end of mandrel 200, and to theupper end of bit housing 224. Lower threads 220 on housing 224 areprovided for conventionally receiving a bit or reamer 222 for drillingthe hole in response to liner rotation. Tube 204 thus includes a centralbore about axis 218 which supplies fluid to the bit 222. Tube 204remains sealed to the housing 224 during axial movement of the tube.

To conduct a tubular drilling or reaming operation, the tool as shown inFIG. 4 may be positioned within the liner 12 after the liner is run atleast partially in the hole, then the liner and the tool lowered to adrilling depth. When the tool is subsequently picked up, fluid fromwithin the interior of the tool may drain out through the ports 202 inhousing 222, so that the entire column of fluid does not have to belifted to the surface with the tool. A seal 223 between tube 204 and thehousing 224 ensures the supply of a high pressure fluid to the bit 222when the tool is positioned as shown in FIG. 4.

The mandrel 200 which surrounds the lower end of mandrel 170 may bethreaded at 216 to housing 222. Mandrel 190 is rotated with the mandrel170, thereby also rotating tube 204. Torque may be transmitted from themandrel 200 to the bit or reamer 222 without torque having to betransmitted through the expander 48.

After the liner 212 or other tubular drilling operation is complete, thedrill pipe 12 may be picked up, thereby lifting the mandrel 170 anddisengaging the clutch 175. Thereafter, the tool may be actuated, asexplained above, so that the expander 48 is forced upward while theliner 12 remains held in place by slips 56, thereby expanding a lengthof the liner during an actuator stroking operation. As previouslydiscussed, the slip resetting and stroking operation may be repeateduntil a desired length of the liner is expanded, after which time theliner is fixed at its lower end in the well, and an upward force on adrill pipe may be used to expand upper sections of the liner withoutstroking the tool.

The tool as disclosed herein may be recocked during an upward strokingoperation, then the hydraulic section activated to set the slips and topull up on the expander and expand a length of the tubular. The tool maybe used to expand a tubular in an open hole operation, and may also beused to press a tubular tightly against the wall of another tubular in acladding operation. Moreover, the technique is able to reliably expandoverlapping joints of pipe sections which are expanded, therebyproviding a monodiameter or continuous ID bore application.

The above application discloses elongate components, such as a toolmandrel and an outer sleeve exterior of the tool mandrel, which inpractice are each a series of interconnected components, so the toolmandrel and the outer sleeve are each an assembly of a plurality ofinterconnected tool mandrel sections and a plurality of outer sleevesections. Accordingly, each of these terms as used herein should beunderstood to include a plurality of sections which together form theelongate components.

Although specific embodiments of the invention have been describedherein in some detail, this has been done solely for the purposes ofexplaining the various aspects of the invention, and is not intended tolimit the scope of the invention as defined in the claims which follow.Those skilled in the art will understand that the embodiment shown anddescribed is exemplary, and various other substitutions, alterations andmodifications, including but not limited to those design alternativesspecifically discussed herein, may be made in the practice of theinvention without departing from its scope.

1. A hydraulically powered downhole tool for axially moving an expanderin a well to radially expand a downhole tubular, comprising: a toolmandrel axially secured to the expander, the tool mandrel including aplurality of mandrel sections each having a lower end forinterconnection with an upper end of another tool mandrel section; aplurality of pistons each axially movable relative to the tool mandreland mechanically interconnected by an outer sleeve exterior of the toolmandrel; one or more slips supported by the outer sleeve to temporarilyfix an axial position of the outer sleeve in the well; the outer sleeveincluding the plurality of outer sleeve sections each having a lower endfor interconnection to an upper end of another outer sleeve section; anda retainer for supporting an upper outer sleeve section axially above alower outer sleeve section, thereby exposing upper and lower mandrelsections for assembly, the upper outer sleeve section being axiallylowered over the assembled upper and lower mandrel sections forconnection with the lower outer sleeve section.
 2. A downhole tool asdefined in claim 1, wherein hydraulic fluid is supplied to the pluralityof pistons through a workstring having an interior in fluidcommunication with an interior bore in the tool mandrel.
 3. A downholetool as defined in claim 1, wherein the one or more slips include aplurality of circumferentially spaced slips for engaging an inner wallof the downhole tubular in the well.
 4. A downhole tool as defined inclaim 1, further comprising: another plurality of pistons each axiallymovable relative to the outer sleeve and mechanically interconnected tothe tool mandrel.
 5. A downhole tool as defined in claim 1, wherein thetool mandrel includes upper and lower sections interconnected by athreaded pin and box connection.
 6. A downhole tool as defined in claim1, wherein the outer sleeve includes upper and lower sectionsinterconnected by a threaded connection.
 7. A downhole tool as definedin claim 1, wherein the retainer comprises threads secured to themandrel; and through ports in the mandrel supply fluid pressure to theplurality of pistons.
 8. A downhole tool as defined in claim 1, whereineach of the one or more slips and the outer sleeve include cam portionsto force the slips radially outward in response to axial movement of thetool mandrel relative to the outer sleeve.
 9. A downhole tool as definedin claim 1, wherein the tool is assembled with a substantially verticalassembly axis at a well site.
 10. A hydraulically powered downhole toolcomprising: a tool mandrel having an interior bore; a plurality ofpistons each axially movable relative to the tool mandrel andmechanically interconnected by an outer sleeve exterior of the toolmandrel; another plurality of pistons each axially movable relative tothe outer sleeve and mechanically interconnected to the tool mandrel; awork string supplying hydraulic fluid to the plurality of pistons andthe another plurality of pistons through an interior of the work stringin fluid communication with the interior bore in the tool mandrel; thetool mandrel including a plurality of mandrel sections each having alower end for interconnection with an upper end of another tool mandrelsection; the outer sleeve including the plurality of outer sleevesections each having a lower end for interconnection to an upper end ofanother outer sleeve section; and a retainer for supporting an upperouter sleeve section axially above a respective lower outer sleevesection, thereby exposing upper and lower mandrel sections for assembly,the upper outer sleeve section being axially lowered over the assembledupper and lower mandrel sections connection with the respective lowerouter sleeve section.
 11. A downhole tool as defined in claim 10,wherein the tool mandrel includes upper and lower sectionsinterconnected by a threaded pin and box connection.
 12. A downhole toolas defined in claim 10, wherein the outer sleeve includes upper andlower sections interconnected by a threaded connection.
 13. A downholetool as defined in claim 10, wherein the retainer comprises a latch totemporarily secure an axial position of an outer sleeve section withrespect to the tool mandrel.
 14. A downhole tool as defined in claim 10,wherein through ports in the mandrel supply fluid pressure to theplurality of pistons.
 15. A downhole tool as defined in claim 10,further comprising: a plurality of circumferentially spaced slipssupported by the outer sleeve for engaging the downhole tubular in thewell to temporarily fix an axial position of the outer sleeve in thewell.
 16. A method of assembling a hydraulically powered downhole toolat a well site, comprising: providing a tool mandrel having an interiorbore; providing a plurality of pistons each axially movable relative tothe tool mandrel and mechanically interconnected by an outer sleeveexterior of the tool mandrel; the tool mandrel including a plurality ofmandrel sections each having a lower end for interconnection with anupper end of another tool mandrel section; the outer sleeve including aplurality of outer upper sleeve sections each having a lower end forinterconnection to an upper end of an outer lower sleeve section;temporarily supporting each of the outer sleeve sections axially above arespective lower outer sleeve section; thereafter interconnecting twomandrel section; thereafter axially lowering the outer sleeve sectionover the interconnected mandrel section; and thereafter assembling theouter sleeve section and the outer lower sleeve section.
 17. A method asdefined in claim 16, further comprising: supplying hydraulic fluid tothe plurality of pistons through a workstring having an interior influid communication with the interior bore in the tool mandrel.
 18. Amethod as defined in claim 16, wherein the tool mandrel includes upperand lower sections interconnected by a threaded pin and box connection.19. A method as defined in claim 16, wherein threads on an exteriorsurface of the mandrel temporarily supports a respective outer sleevesection.
 20. A method as defined in claim 16, further comprising:supporting one or more slips on the outer sleeve to temporarily fix anaxial position of the outer sleeve in the well.